1. Field of the Invention
The present invention relates generally to a metal tubular fencing system and to a coupling used in such a system for coupling the fence rails and fence posts of metal tubular fences of the type used in horse and cattle ranching operations.
2. Description of the Prior Art
Modern livestock fences, particularly those used for horse and cattle operations, are often formed from horizontally extending, tubular metal (galvanized steel) rails mounted on vertical tubular posts anchored to the ground. The tubular steel components are typically corrosion protected, as by powder coating, or similar techniques. This type of “tubular steel fence” is widely considered to be superior to traditional split rail and other types of fences because it is rigid and extremely durable. However, in the past, the individual rail sections of the typical steel fence were required to be welded to the vertical fence posts. This welding requirement adds considerable time and labor to building the fence because a portable welder must be employed to weld the opposite ends of each and every rail to the posts on which it is supported. The welds must then be ground to a smooth finish and painted or coated with a protective coating. The welds are subject to rust and peeling, requiring periodic maintenance for the lifetime of the fence.
More recently, a non-welded connector for steel fences has been introduced. This connector, known as the “440 Fence™” connector, is manufactured by the 440 Fence Company of Aubrey, Tex. It is described in U.S. Patent Publication No. 2008/0042116, published Feb. 21, 2008. It is also the subject matter of U.S. Design Pat. No. 495,434. The 440 Fence utilizes two stacked connectors at each joint in the fence. Each connector has a vertical section for slipping over the fence post and a generally horizontal section that receives the end of a rail section. The horizontal section is hinged to the vertical section so as to permit limited pivoting of the horizontal section relative to the vertical section in order to accommodate inclines of the fence. With these connectors, a steel fence can be built without welding, which offers the advantage of significantly reducing labor when compared to traditional steel fence construction. Post-assembly maintenance is also reduced.
However, the 440 Fence™ connector and other connectors presently available in the marketplace still suffer from various drawbacks. For instance, the 440 Fence™ connector and other presently available designs do not utilize mating clamping body pieces to join the connector to the horizontal rail. Instead, the horizontal body piece is received in a one piece tubular body member which is then secured to the horizontal rail by one or more set screws.
The set screw method has several disadvantages. When tightening the set screw, it will tend to penetrate the powder coated paint which is typically used to coat the fence rails, as well as the zinc coating that is on the outside of the tubular pipe, before eventually digging into the bare metal pipe. This can result in exposing bare metal and allow corrosion to begin. If the set screw is severely over tightened, then this can result in deforming the pipe by actually denting the pipe. The set screw design also limits the amount of surface area contact that can be used to hold the pipe, since it is relying on the diameter of the set screw on one side and the contact of the inside and outside diameters of the pipe on the other. Some of these same negative features are present when using set screws on the vertical posts, as well.
A need has therefore arisen for a fence connector or coupling of the above type which uses “clamping” components, rather than set screws to secure the fence components in place.
The use of a two component clamping assembly would allow the fence to be assembled using two different methods because the components that are used to clamp on the horizontal rail are comprised of two pieces. This would allow the fence to be assembled either with both of these pieces being put together first and the pipe inserted later or the pipe can be inserted as these two pieces are being put together. Having this capability is more important if the fence needed to be repaired after the initial installation.
The use of clamping components, rather than the described set screw mounting method is also important because, if the rail is allowed to float as where there are changes in the soil, it can cause the vertical post to shift which can result in the post pulling away from the rail to the point where it comes loose. Also, if livestock contact the rails secured with the set screw method, there is more of a possibility that the rail can flex and the connector and rail can pull loose. Using clamping components on the rail helps prevent this from happening. The strongest fence coupling would feature a pair of mirror image clamping components which allow for near 360° of clamping on both the horizontal rail and the vertical post.